Azolla pinnata - Water fern

Azolla pinnata is a small floating plant that is added to the surface of a pond or pool (fresh and stagnant water). This aquatic fern forms a dense carpet not exceeding 15 cm in height and tends to spread horizontally. Its fronds consist of 1 to 2 mm long, imbricated scales, forming a very dense network. They are green and turn purple-red when exposed to the sun. They usually disappear in winter due to the cold.

From the Salvinaceae family, Azolla pinnata is an aquatic fern native to Southeast Asia and East Africa. It grows in ponds, river marshes, canals, and even rice fields. It is a lover of fresh and stagnant water. It has been present in rice fields for hundreds of years and even serves as organic fertilizer. Its fronds harbor a cyanobacterium, Anabaena azollae, which fixes atmospheric nitrogen and releases it into the water.

This fern, with tropical origins, appreciates heat and calm, warm freshwater. It quickly covers a body of water. To control its growth, do not hesitate to remove some plants. Add some oxygenating plants to your pond, such as Elodea canadensis or Hippuris vulgaris, which have purifying properties. On the edges, add some color with Iris ensata Gusto with blue flowers and Lysimachia lichiangensis with yellow flowers.  Equisetum fluviatile, also known as River Horsetail, will bring verticality and uniqueness to the ensemble. It is also an excellent aquarium plant.